Changes in energy stores

Question	Answer
What is the name of the energy stored by a moving object?	Kinetic energy is stored by a moving object.
Where might elastic potential energy be stored?	Elastic potential energy can be stored in a stretched catapult.
What is the main energy transfer for an apple falling from a tree?	Falling objects lose gravitational potential and gain kinetic energy.
What is the main energy transfer for a long-distance runner?	Runners transfer chemical energy into kinetic energy.
If 4,000 J of energy is transferred and 2,500 J is usefully stored, how much energy is wasted?	1,500 J of energy is wasted. Wasted energy = total energy transferred - useful energy.
What happens to 'dissipated' energy?	Dissipated energy is lost to the surroundings.
What is the gravitational potential energy stored in a 60 kg child sitting at the top of a 2 m high slide? (g = 10 N/kg)	gPE = mass × gravity × height = 60 × 10 × 2 = 1,200 J
The spring constant of a spring is 25 N/m. The spring is extended by 50 cm. How much elastic potential energy is stored?	Extension must be in metres, so 50 cm = 0.5 m. ePe = ½ k e2 = ½ × 25 × 0.52 = 3.125 J
A 4 kg ball has 50 J of kinetic energy. How fast is it moving?	KE = ½ m v2, 50 = ½ x 4 × v2, 25 = v2, v = 5 m/s

Resource summary

	Created by A̷̋̍́̄́̈́́̓̽̍̌̈́͂̿̒̌̾̊̋̚̚͠͝͝ᒪᓰ -A̷̘̋̍́̄́̈́́̓̽̍̌̈́͂̿̒̌̾̊̋͌̚̚͠͝͝ about 6 years ago